Dehydration of organic compounds by catalytic action



oct. 7, 1.9.47. H. MgLLER DEHYDRATION 0F ORGANIC COMPONDS BY CATALYTICAQTION Filed Aug. 5, 1942 Q filed November 6, 1939. 4'

Patented Oct. 7, 1947 DEHYDRATION OF ORGANIC COMPOUNDS BY vCATALYTICACTION.

HarryMilier, Columbia; M0., aSSgior tolilational' l .L t

Agrol Company, Inc.

I New York, N. Y.; a corpof ration of Delaware Application Augusta,1.942. serial No. 454,105

This invention relates to a catalytic process l and more particularly toa method of removing the elements of water from organic aliphaticyesters of high molecular weight by catalytic ac-` tion. rThis,application is a continuation impart of myl pending application SerialNo. 303,169,

One of the objects of my invention is hydrogen atom on adjacent carbonatoms.

to provide.

- anovel method for vremovingthe elements 'of water by catalytic actionfrom'organicqaliphatic esters having at least one hydroxyl group and oney 7 Claims. (Cl. ZBO-405.5)

, 2 selected oxide to form a catalytic mass of nonsintered individualparticles which pourv freely and do not losetheir original shape.

During the formation of this catalyst, the selected oxide is reducedtoform a promotive oxide and a salt is formed by .the reaction of aportion of the oxide of the metal of the skeletal core withV theactiveoxide. A substantial portion of the l. metal oi the skeletal coreremains free however vA further object of my invention is tov provide `Aa method of removing onev molecule, of'waterfrom each fatty acidradical` contained'. in the triglyceride oi' ricinoleic acid presentincastor oil.

With these and other objects in view,v my in vention `embraces broadlythe concept of removing the elements of water in thezproportions to formwater from certain types' of organiccompounds by heating the compoundandbringing it into contact with an especially prepared catalyst.' Thecatalyst used in this processcomprises a` `granular base metal and apromotive'oxide in 4 pellet form. The base metal is selected from agroup consisting of aluminum, magnesium and I beryllium. The promotiveOXidecOmpriSes an oxide selected from family A of the-sixth group of theperiodic table, such as anoxide of tung--v sten, chromium, molybdenum,uranium, and tellurium.

The selected oxide must be capableof partial reduction and the basemetalemployed must have a lower melting point than the selected oxide toprevent sintering. In this connectionjit ,should be noted that aluminumand magnesium have a lower melting point Ithan any of the oxides ofFamily A of the Sixth Group of the Periodic Table and, therefore, can beemployed with any of the suitable oxides.

In preparing the catalyst, the selected materials are brought intointimate contact by a rubbing action or any other suitable means and themixture is heated to, or near, the melting point of the base metal.

a'nd serves as a reductionv reserve for the partially -l reduced acidicoxide which is the active promotivev agent. For example. if aluminum isselected as a lbase metal and tungstlc trioxide to form thev pro-.

motive oxide, the aluminum when'heated to approxmately its own meltingpoint will react with .the tungstic trioxide to ,form a blue oxide oftung- -'sten (W205i and some aluminum tungstate. The remaining freemetal together with some aluminumoxide forms a skeletal core structurevthat preserves the activity of the reduced oxide.' In other words,thealuminum serves to'hold the aluminum tungstate in equilibrium withthe reduced andunreduced oxides of tungsten, there- A. by bringng'aboutthe constant reduction of the 'I'he contact of the molten base metalwith the selected oxide results in the formation of a skeletal core ofactive metal which penetrates the mterstices o1 the non-sinteredparticles of the tung'stic trioxide into the blue oxide of tungsten.Such a catalyst because of its great activity and thefact that it mayvbe used for long periods without renewal' is especially suited for thedehydration of organic compounds such as castor oil. In this connection,however, it should be noted that as total oxidation destroys theproperty of the catvfalyst, itfis advisable to occasionally subject thecatalytic mass to the reductive activity of hydrogen.

The size 'of the granular particles of the base metal will vary within arange of from l0 to 30 mesh.- -The proportions ofthe base metal andpromotive oxide will also vary depending upon the metals which areselected. For example, where tungstic anhydride is selected as thepromotive oxide and aluminum or beryllium as a base metal, it has beenfound that` the presence of approximately 10% by weight of the anhydrideis v suicient.

The catalyst produced by the described process'has strong dehydrativeproperties which are eiective from room temperature to approximately 600C. and are especially effective from approximately to 400 C. y

In general,l the present invention relates to a 5 process of dehydratingaliphatic organic esters,

having a hydroxyl group and a hydrogen atom on adjacent carbon atoms, bybringing these compounds into contact with the especially selectedactivated catalyst previously mentioned. In order to obtain maximumdehydration, the material is brought into a series of successivecontacts with the catalyst. Immediately after each contact with thecatalyst, the newly formed water of dehydration is removed in vaporform.

In order to illustrate my invention, I will now describe my process asadapted to the dehydration of castor oil, it being understood that thisprocess can also be applied to the dehydration of other organiccompounds of similar structure, such as esters of lactic acid down toand including butyl lactate. It is also possible that propyl lactate maybe dehydrated, but the lactates below propyl are too volatile and mustbe handled in a vapor phase. The use of these volatile compounds wouldnecessitate a modification in the process to be described.

As shown diagrammatically in the drawing, the equipment used in thedehydration of castor oil Rand similar oils consists of a series ofchambers I in each of which is placed the selected dehydrative catalyst2. The upper portion of each of the chambers I is connected by means ofducts 3 with a conduit 4 which leads to a steam ejector and barometriccondenser which is not shown. By means of this equipment a partialvacuum can be created within the chambers i In the-operation, the oil isforced by pump 5 into a heater 6 where it is heated to a temperal turepreferably of from 240 to 260 C. and is then passed through the chambersI. Each chamber discharges into the next one before it actually fills,thereby leaving a space above the oil level in each chamber. A partialvacuum, preferably one which will support twenty-ve inches of mercury,is maintained in the chambers.

In passing over the catalyst, one molecule of water is removed from eachfatty acid radical in the triglyceride of ricinoleic acid contained .inthe castor oil. This newly formed water in the form of water vaporleaves the surface of the oil in each chamber and passes out through thevacuum system conduits 3 and 4.

After leaving the last chamber I, the oil passes through a continuouscentrifuge 1 which concentrates the entrained catalyst and returns it bymeans of the conduit 8 to the oil supply. The remainder of the oil ispassed on to any subsequent processes which it may be desired to employ.Any highly subdivided catalyst which maybe suspended in this oil may beremoved by filtration or further centrifugal action as indicated at 9.

The number of chambers used in the process will vary in accordance withthe operative characteristics desired and the substance being treated isfed at a rate which depends on the type of substance being treated andthe degree of dehydra tion desired.

When the process is utilized for the dehydration of castor oil, dryingoil having the drying properties approaching those of tung oil isproduced which is therefore suitable for paints and varnishes and isalso useful for all the other purposes for which tung oil may beemployed.

Castor'oil is essentially the triglyceride of ricinoleic acid. Theformula is Dehydration of the ricinoleic acid radical at the hydroxyllinkage could result in creating a double bond in one of two places, i.e.,

( 1) CH3 (CH2) 4.CH=CH CH2CH=CH (CH2) 'JCOOR (2) CH3. (CH2)sCH=CH-CH=CH. (CH2) 'ICOOR' (R indicates the remainder oi thetriglyceride molecule.)

When the triglyceride of ricinoleic acid is dehydrated in the mannerdisclosed herein, the iodine value is not materially changed, indicatingthat the dehydration took place in accordance with Formula 2 above,forming what is termed a conjugated system, that is a. system of fourcarbon atoms with the double bonded carbons separated by a single bondedpair. Conjugated double bonds add halogens in the same proportions assingle double bonds.

The following data show the advantage the catalytic pellets describedabove will display over mixed oxides prepared in the usual manner forthe dehydration of castor oil.

The pellet retains its activity during the dehydration of 1000 times itsweight of castor oil. Mixed oxides prepared in the usual manner(ordinary mixture above) begin to lose their activity after 500 or 600times their weight of cil has been dehydrated.

While for purposes of illustration I have described my process asadjusted for the dehydration of castor oil, it is intended thatthisprocess should be used for the dehydration of similar organicesters. I, therefore, wish it understood that I intend that thisinvention be only limited by the prior art and the scope of the appendedclaims.

I claim:

l. The method of dehydrating an oil consisting essentially of glycerylesters of ricinoleic acid, comprising `heating the ester to atemperature of from 100 to 600 C. and then bringing the organic compoundinto contact with a catalyst comprising a skeletal core of a base metalselected from the group consisting of aluminum, magnesium and berylliumwhich is positioned within'the interstices of the non-sintered particlesof a partially reduced oxide selected from the elements of family A ofthe sixth group of y the periodic table, saidskeletal core serving asselected from the group consisting of aluminum, magnesium and berylliumwhich is positioned within the interstices of the non-sintered particlesof a partially reduced oxide selected-from the elements of family A ofthe sixth group of the periodic table, said skeletal core serving as areduction reserve against the oxidation of the said partly reducedoxide.

3. The method of dehydrating castor oil comprising heating the castoroil to a temperature within a range of from 240 to 260 C. and thenbringing the heated oil into contact with a catalyst comprising askeletal core of a base metal selected from the group consisting ofaluminum, magnesium and beryllium which is positioned Within theinterstices of the non-sintered particles of a partially reduced oxideselected from the elements of family A of the sixth group of theperiodic table, said skeletal core serving as a reduction reserveagainst the oxidation of the said partly reduced oxide.

4. The method of dehydrating castor oil comprising heating the castoroil to a temperature Within a range of from 100 to 600 C. and thenbringing the heated oil into a series of successive contacts with acatalyst comprising a. skeletal core of a base metal selected from ythegroup consisting of aluminum, magnesium and beryllium which ispositioned Within the interstices of the non-sintered particles of apartially reduced oxide selected from the elements of family A of thesixth group of the periodic table, said skeletal core serving as areduction reserve against the oxidation of the said partly reducedoxide.

5. The method of dehydrating castor oil comprlslng heating the castoroil to a temperature within a range of from 240 to 260 C. and thenbringing the heated oil into a series of successive contacts with acatalyst comprising a. skeletal core of a base metal selected from thegroup consisting of aluminum, magnesium and beryllium which ispositioned within the interstices of the non-sintered particles of a.partially reduced oxide selected from the elements of family A of thesixth group of the periodic table, said skeletal core serving as areduction reserve against the oxidation of the said partly reducedoxide.

6. The method of dehydrating castor oil comprising heating the castoroil to a temperature within a range of from 240 to 260 C., bringing theheated oil into a series of successive contacts with a. catalyst andthen removing the newly formed water. vapor by vacuum after eachsuccessive contact, said catalyst comprising a skeletal core of a basemetal selected fromvthe group consisting of aluminum. magnesium andberyllium which is positioned within the interstices of the non-sinteredparticles of a partially reduced oxide selected from the elements 0ffamily A of the sixth group of the periodic table, said skeletal coreserving as a reduction reserve against the oxidation of the said partlyreduced oxide.

7. The method of dehydrating castor oil comprising heating the castoroil to a temperature within a range of from to 600 C., bringing theheated oil into a series of successive contacts with a catalyst and thenremoving the newly formed water vapor by vacuum after each successivecontact, said catalyst comprising a skeletal core of a base metalselected from the group consisting of aluminum, magnesium and beryl liumwhich is positioned Within the interstices of the non-sintered particlesof a partially reduced oxideselected from the elements of family A ofthe sixth group of the periodic table, said skeletal core serving as areduction reserve against the oxidation of the said partly reducedoxide. f

HARRY MILLER..

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,374,589 Levey Apr. 12, 1921FOREIGN PATENTS Number Country Date 317,391 Great Britain June 16, 1930830,494 France May 16, 1938

